fail-fast object destructuring

[Brendan Eich]

Brendan Eich wrote:
> and implemented in SpiderMonkey, Rhino, and Opera [...]

Note implementations.

>> (And that is leaving aside all usability considerations for a moment.)

I meant to add that we have some usability experience, user-testing and 
bug-reporting by various means, based on the implementations. Imputing 
undefined for missing properties has not been an issue. The ToObject has 
not been an issue. You can discount this since it's just anecdotal or 
whatever. It counts for something with me, especially compared to 
speculations and assertions that there's a big problem. If there were, 
wouldn't we know by now?

/be